Twin US820's = 268cc = 16.35 cu in's ............

This project is already underway and partly built using two US820's sitting side by side.
Both engines will be modded to Copperhead / Vintage standard.
Both engines will be decompressed for easier starting.
I have a left and a right engine to be used in this project.

The drive for the bar and chain will be a centre drive.
The bar mount and oil tank is off a McCulloch SP125.

The Clutch is off a US820 powered chainsaw and is an outboard type.
The cranks will be joined at 180 degree to each other to allow smoother power.
For test purposes i'll get two adaptors made from the coupling one at 180 degree
and another to fire simutaniously as that coupling will provide more power.

The two engines will be mounted on flat plate with a central upright plate that will have the oil tank mounted to it.

The saw will be auto oiling and have a manual oiler as well.
The saw will be fully cushioned to reduce vibration using the full frame work from a McCulloch SP125.

Changing a chain is the hassle running two engines side by side so to remove or change the chain one engine will be unbolted and the coupling i have being made will allow this and slide off the keyed crank of the right hand engine.

At this stage i'll be running two Tillerton HR carbs mounted on Gem V-12 reed blocks and velocity stacks.

Both engines will run PVL ignition units.

As more progress is made i'll add photos and more details ................. Mc Bob
=======================================================

Update 1 st Nov 2009

The 4 x US820 engines i have had for quite a while and are the core engines that will be used in the engine rebuilds.
The basic two engines will be copied and modded to the porting of the Copperhead / Vintage level.

Update Nov 11 2009

The Copperhead conrods, new needle races and Dave Bonbright rod bolts are here, i still await the special boost port pistons but they should be here any old time.

I have to make the girdle for the heads to ensure that if the heads or the top of the cylinders decide enough is enough and part with the lower section of the crankcase at the port level i'll have the option of keeping my left hand on the end of my arm where it belongs.

Update 27th Nov 09

The pistons have arrived these will give me something to do over Xmas fella's as i can start the porting and sundry mods to both cylinders.